Wood grinder



April 29 1924.

P. PRIEM woob' GRINDER Original Filed Feb. 24, 1923 INVENTOR P/ZUL PP/EM BY J/ WM ATTCRN EYS Patented Apr. 29, 1924.

3 UNITED STATES A 1,492,390 PATENT OFFICE.

PAUL PRIE M; OI-HEIDENHEIM, GERMANY, ASSIGNOR TO AMERICAN VOI'IH OONTAGT COMPANY, INC., 01 NEW YORK, N. Y., AflORPOIZATION OF NEW YORK.

woon cnm nan.

Originalapplicatlon illedl'ebruary 24,. 1923, Serial No. 631,117. Divided and this application filed December 10, 1923.

To all wlwm it may concern: 1

Be it known that I, PAUL PRIEM, a citizen of the Re ublic of Germany, and residing at Heiden ieim an der Brenz, Germany, have invented certainnew and useful Improvements in Wood Grinders, of which the following is a specification.

My invention relates to wood grinders 'of the mechanical feed type, and the object of my invention is to provide means for so automatically regulating the feed that the pressure of the char eagainst the stone is maintained substantlally uniform, so that the speed and load of the stone may be maintained substantially constant. The regulation of the feed of the charge is accomplished through means automatically responsive to the varying power demands on the motor which drives the stone.

The underlying thought is susceptible of embodimen in various forms of equipment, some of which are illustrated. in my copending application Serial No.'621,117, filed February 24, 1923;0f which the present application is a division.

In the accompanying drawings- Fig. 1 is a more orless diagrammatic side elevation of an installation in which my invention is embodied in one form; and

Fig. 2 is a similar view of a modified construction.

Referring to Fig. 1, I have indicated at 5 an electric motor of constant speed type,

which drives the grind stone 6 through any suitable operating connection, such as a belt or chain 7. Associated with the grind stone is a press chamber 8 faced on .op 'osite sides by feed chains 9 and 10 support able frame work 11 and servin to advance and press the charge against t e stone. At their lower ends the chains pass around the sprockets 12 on the, shafts 13, carrying worm wheels 14 which mesh with the worms 15 on shaft 16, which has at one end a bevel gear 17. Meshing with the latter is a cooperating bevel p nion 13 on the shaft of the pulley 19, around whlch asses a drlving belt or chain 20 from to pulley 21. The shaft of the pulleyfcarries a gear 22 meshing with a cooperating gear 23 driven by the rotary ump 24 which operates as a fluid 'motor. e fluid which drives the pump 24 is delivered thereto from a second pump 25 of the same or difl'erent type, the

on a'suit- Serial No. 679,853.

' charges the fluid again to the tank 28.

Arrangrd in the piping 29 is a control valve 30, the valve stem 31 of which is connected with acore 32 of the solenoid winding 33 arranged in the circuit of the motor 5. Thesolenoid core is attached at its upper end to the lever 34, pivoted at 35 and adjustably counter-weighted at 36.

As the current demand of the constant speed motor 5 varies with the load im osed upon the stone 6 by the charge throug the press chains 9 and 10, the fluctuation of current varies the position of the solenoid core 32 and thus opens or closes valve 30 by moving the valve stem 31 up or down. When the current demand of constant speed motor 5 increases with the increasing load the solenoid core 32 moves downwardly, t ereby, closing the valve 30 -When the current demand of the constant s ed motor 5 decreases with decreasin loa the solenoid core 32 moves upwar thereby open,- ing the valve 30. In this way, more or less fluid is delivered by the pump 25 to the pump 24. Inasmuch as the latter drives the press chains 9 and 10 it is obvious that [variation of the load upon the grind stone causes a variation in the drive'of the feed chains through the throttling of valve 30 in accordance with the current demand upon the grind stone driving motor 5. y

The same thought is embodied in the construction shown in Fig. 2, in which the drive of the stone 6 is similar to that shown in Fig. 1. Instead of the continuous 'feed arrangement for advancing the charge against the stone, however, I have here shown asso ciated with the grind stone a series of reciprocating press plungers 37, each working in its independent feed chamber 38 to force its charge of wood blocks 39 against the stone. Each of the plungers isfed forward by a pinion 40 meshing with a rack 41 on the stem ofa plunger, the pinion 40 being driven through a chain connection 42, and the sprocket of the latter being driven by a chain 43 from a sprocket 44 on the shaft of the pulley 45. The pulley 45 is driven through a belt or phain 46 passing around the driving pulley or gear 47 on the shaft 48 of a turbine 49. The gas or fluid which drives the turbine 49 enters through the pipe 50 in which is arranged a valve 51, the stem 52 of which is connected to the solenoid core 32 which, as in Fig. 1, is hung from one end of the lever 34 pivoted at 85 and counterweighted at 36. The winding 33 of the solenoid is arranged in the circuit of the stone driving motor 5.

The operation is analogous to that-first described. As the load on the stone varies, with consequent variation of the current input to the motor 5, the solenoid core 32 rises and falls and thus opens or closes the valve 51 by moving the valve stem up or down and thus controlling the flow to the press feed turbine 49. The feed of the press is thus varied and the drive of the stone at substantially constant speed and load is secured.

It will be understood that various modifications in detail may be made without departing from what I claim as my invention.

I claim 1. In a wood grinder installation, a grind stone, a motor for driving the same, a press for mechanicall feeding a charge of wood blocks against t is stone, a feed gear for advancing the press, a fluid driven member for actuating the feed gear, and means auto: matically operated by variations in the stone drive conditions incident to varying load on the stone, for controlling the supply of fluid to the fluid-driven member by which the feed gear is operated.

2. In a wood grinder installation, a grind stone, a motor for driving the same, apress for feeding a charge of wood blocks against the stone, a feed gear for advancing the press, a rotary pump actin as a motor and driving the feed gear, and means for controlling the fluid pressure 'on the rotary pump, so as to maintain substantially constant the load on the grind stone.

3. In a wood grinder installation, a grind stone, a motor for driving the same, a press for mechanicall feeding a charge of wood blocks against the stone, :1 feed gear for advancing the ress, a rotary pump acting as a motor and di'iving the feed gear, a second rotary pump, means for driving the same to produce fluid pressure, a piping between the two pumps, and means for controlling the fiuid pressure in said piping to maintainsubstantially constant the load on the grind stone.

4. In a wood grinder installation, a grind stone, a motor for driving the same, a. press for mechanically feeding a charge of wood blocks against the stone, a feed gear for advancing the press, a rotary pump acting as a motor and driving the feed gear, a second rotary pump, means for driving the same to produce fluid pressure, a pipin between the two pumps, a tank from whic the fluid is" taken by oneof the pumps and to which the fluid is returned by the other punip, and means for controlling the fluid pressure in the piping between the pumps, so as to maintain substantially constant the load on the grind stone.

In testimony whereof I have signed my name to this specification.

PAUL PRIEM. 

